The overestimation, however, is of no great significance, for data will be introduced a little later which show definitely that the underestimation or overestimation of a given standard is determined, among other factors, by the intensity of the stimulation employed. The apparently anomalous results obtained in the early investigations are in part probably explicable on this basis. As regards the results of _practice_, the data obtained from the two subjects on whom the greatest number of tests was made (_Hs_ and _Sh_) is sufficiently explicit. The errors for each successive group of 25 series for these two subjects are given in Table III. TABLE III. _ST_ = 5.0 SECONDS. SUBJECT _Hs_. SUBJECT _Sh_. CT (1) (2) (3) (4) (1) (2) (3) (4) 4. 2.5 2.5 1.5 2.5 0. .5 0. .5 4.5 6.0 3.0 3.5 7.0 5.0 3.5 2.0 .5 5. 14.0 11.0 11.0 11.0 8.5 11.5 4.0 7.0 5.5 11.5 11.5 6.0 12.5 11.0 16.0 14.0 15.0 6. 12.0 9.0 6.5 6.0 3.5 2.0 1.5 1.0 6.5 4.0 3.5 4.0 3.5 4.0 .5 0. 0. No influence arising from practice is discoverable from this table, and we may safely conclude that this hypothetical factor may be disregarded, although among the experimenters on auditory time Mehner[13] thought results gotten without a maximum of practice are worthless, while Meumann[14] thinks that unpracticed and hence unsophisticated subjects are most apt to give unbiased results, as with more experience they tend to fall into ruts and exaggerate their mistakes. The only stipulation we feel it necessary to make in this connection is that the subject be given enough preliminary tests to make him thoroughly familiar with the conditions of the experiment. [13] _op. cit._, S. 558, S. 595. [14] _op. cit._ (II.), S. 284. 2. The second group of experiments introduced the factor of a difference between the stimulation marking the end of an interval and that marking the beginning, in the form of a change in locality stimulated, from one finger to the other, either on the same hand or on the other hand. Two classes of series were given, in one of which the change was introduced in the standard interval, and in the other class in the compared interval.